114 . SECRETS OF ANIMAL LIFE 



by the temperature and oxygenation of the water 

 and so on; they are impelled by an internal spur 

 a seasonal change of constitution; but in thinking 

 over this return to their natal waters, or to waters 

 similar in character, we probably go far wrong in 

 the direction of false simplicity if we do not recog- 

 nize in the salmon struggling against the stream a 

 bent bow that is more than material. We mean that 

 in its way the salmon is a personality a piscine 

 personality if you will with a life not only of 

 contracting and relaxing, digestion and combustion, 

 and so on, but a life of feeling and willing besides, 

 the two making one. And just as the salmon 

 illustrates an intensely active genetic impulse, the 

 expression of physiological and psychical enregistra- 

 tions both racial and personal, so in these wind- 

 borne clouds of winged fruits and parachuted seeds 

 we see on a very different level and with little hint 

 of " the bent bow " the same fascinating problem 

 of adaptations which secure the continuance of the 

 race from generation to generation. 



The familiar withering and fall of the leaves 

 can never fail to excite the interest of those who 

 keep alive the curious spirit. What busy synthetic 

 laboratories they have been all the summer through, 

 what abundance of complex carbon compounds 

 have they manufactured! and now the laboratory 

 furnishings are worn out and the leaves must die. 

 But there is high art in their dying; for there is a 

 migration of almost all that is valuable from leaf to 

 stem, so that little more than waste is left to fall; 



